The present invention relates to an autonomous or controlled unitary rolling vehicle capable of moving in various environments, including indoors, outdoors as well as the planetary bodies such as planets and the Moon.
A unitary rolling vehicle is defined as a vehicle with a rolling member arranged for rolling movement, comprising a drive system supported by the rolling member and arranged to drive the rolling member for rotation, wherein the centre of mass of the drive system is lower compared to the centre of the rolling member in the vertical direction at rest and the drive system is further arranged to displace a drive mass with respect to the rolling member thereby moving the mass centre of the vehicle to achieve a driving force. The main rolling member be of any suitable shape that allows a rolling movement, such as a sphere or a ball, an ellipsoid, a torus or a wheel, combinations thereof or the like.
Upon designing a unitary rolling vehicle, one difficulty is to make it sufficiently robust to sustain all environmental and operating conditions: shocks, stairs, carpets, various obstacles, radiation, thermal fluctuations, or direct manipulation of people or other rolling vehicles, etc. A further difficulty is to design a control system that stabilizes the unitary rolling vehicle when the vehicle is under impact of said conditions.
In the attempts to design a stable unitary rolling vehicle that takes environmental and operating conditions into consideration, a mathematical model of the vehicle has been designed that after time learns to control all possible states of the vehicle, see the prior art document WO 2006/049559. Here a solution is presented that uses a so-called self learning control system based on neural networks.
There are several solutions published how to control a vehicle, described in the following documents: U.S. Pat. Nos. 5,791,425, 6,302,230, EP 1,563,716, U.S. Pat. Nos. 6,289,263, 6,378,634, 6,702,050 and US 2007/0215394. The control systems described are thus designed for simpler system, and are not able to control the complex and complicated situation of controlling a system of a unitary rolling vehicle, especially not when the system is influenced of disturbances.
An important difference between the prior art systems and the system according to the present invention is that the prior art systems are intended to balance an “unbalanced system” and act to maintain the balance, while the system according to the present invention responds to dynamic changes in the movement pattern for the unitary rolling vehicle, where the vehicle constitute a balanced system, and the system compensates for the dynamic changes.
The prior art unitary rolling vehicle can be divided into two major groups:                Pendulum type comprising a main axis connected diametrically to a rolling member and supporting a drive mechanism arranged to drive a ballast pendulum for rotation around the main axis.        Shell drive type with a drive mechanism that is supported by and moveable along the rolling member inner surface.        
The stabilizing system is aimed at stabilizing all kinds of unitary rolling vehicles, but for illustrative purposes the invention is exemplified with a spherical unitary rolling vehicle of pendulum type.
Due to the displacement of the pendulum centre of mass when driven for rotation about the main axis, the unitary rolling vehicle is put into motion. Moreover, the unitary rolling vehicle may comprise additional equipment in the form of analysis, monitoring, or actuator systems. The rolling member may be of a perfect spherical shape, and/or multi-facetted rolling member formed by a shell with from a minimum of 10 to 30 sides or more. The rolling member can be elongated or shaped in any way as long as one main axis that is suitable for rotation around is preserved. The outer surface of the rolling member can further be provided with a pattern to prevent the unitary rolling vehicle from slipping, sliding sideways or the like.